Reference · Visual workspace
Fill missing values in Visual workspace
Replace missing values with a stated value: a visible label for a category, or a fitted value with a flag for a measurement.
When to use it
Reporting labels such as "unknown"; imputation only when an analysis requires it and the fill is fitted on training data.
How
Add step → Rules → Fill missing for a literal value, or Reshape → Fill with median to learn the value from another table and flag filled rows.
Fill missing region with "unknown"
- The literal is parsed to the column's type.
Pitfalls
- Filling measurements with 0.
- Fitting the fill value on test data.
- Not flagging imputed values.
Lesson: Fill labels, not measurements
Practise it: Label unknown categories, keep missing numbers missing